ZF 8HP45/8HP70 Mechatronic Solenoid Kit, 9-Piece

This is the full nine-solenoid complement for the mechatronic unit inside a ZF 8HP-family automatic: 8HP45, 8HP55, 8HP70 and 8HP90. Those are the eight-speed boxes found under BMW, Audi, Jaguar and Land Rover, and in Chrysler/Dodge/Ram/Jeep form as the 845RE and 8HP70. The kit gives you every pressure-control and shift solenoid that bolts to the valve body, so you replace the whole set at once instead of chasing one failed unit at a time.

Solenoid failure on the 8HP shows up as a harsh or slamming 2-3 shift, shift flare under light throttle, a shudder that feels like torque converter lockup chatter, delayed engagement into Drive or Reverse, and eventually a hard code and limp mode. Because all nine solenoids see the same ATF and the same heat cycles, a single failure usually means the rest are close behind - which is why the kit is the sane repair.

The job is done with the pan off and the mechatronic unit accessible. Drop the pan and filter, drain the fluid, unplug the internal wiring, and remove the retaining clips holding each solenoid to the valve body. The solenoids pull straight out; seat the new ones fully until the clip snaps home and verify each connector is latched before the sleeve goes back on. Reassemble with a new pan and filter, refill with the correct ZF Lifeguard 8 spec fluid, and set the level at the specified fluid temperature - the 8HP has no dipstick and is very sensitive to fill level. Clear codes and run an adaptation reset so the TCM relearns shift pressures.

Note the mechatronic sleeve/adapter and conductor plate are separate parts and are not included here. This kit is the solenoids only.